1. Field of the Invention
The present invention relates to a blower apparatus and particularly, to a blower apparatus which is used in an Over-The-Range (OTR) microwave oven and the like.
2. Description of the Related Art
Generally, an OTR microwave oven is a domestic appliance which is installed over a gas range installed in a kitchen, for performing a cooking function using microwave in a cavity, and at the same time a ventilating function for sucking/discharging combustion gas or polluted air in the kitchen which are generated in a gas range which is installed at the lower side of the OTR microwave oven using a blower apparatus installed therein.
FIG. 1 shows a conventional OTR microwave oven, and it will be described as follows.
As shown in FIG. 1, the conventional OTR microwave oven includes a main body 1 having a cooking space C in which cooking is performed therein by microwave, an outer casing 3 in which the main body 1 is positioned and a flow path 2 is formed at both sides of the main body 1, and a blower apparatus 4 which is installed at the upper rear side of the main body 1.
A rotary tray 5 is rotatably installed inside the cooking space C to rotate food accommodated inside the cooking space C, and a magnetron 8 for generating microwave induced into the cooking space C in case of cooking is installed at the outer side of the cavity.
In addition, an air suction port 6 connected with the flow path 2 is formed at the lower side of the outer casing 3, and an air discharge port 7 for discharging air to the outside is formed on the upper rear surfaces. Here, the air discharge port 7 is connected with a ventilating duct by a connection duct (not shown) such as a building and the like, for the convenience of a user, or the air can be circulated indoors as the air passes through a filter (not shown) which is installed on a front surface of the outer casing 3 by mounting a discharge port of the blower apparatus 4 on the front surface in a building without the ventilating duct.
The conventional OTR microwave oven with the above composition is installed over a gas range, and performs functions of a hood for ventilating smoke and smell generated in cooking by the user as well as the original functions of the microwave oven.
The conventional OTR microwave oven rotates food as the rotary tray 5 rotates when a user opens a door (not shown), puts food on the rotary tray 5 in the cooking space C, closes the door, and pushes an operation button in the adjusting plate (not shown), and at the same time, microwave is generated in a magnetron 8. Therefore, the microwave is induced into the cooking space C, and the microwave oven performs its original function of cooking food using microwave.
Also, when a user pushes a hood operation button on the operation panel, a suction force is generated as the blower apparatus 4 installed in the microwave oven is operated, and as shown dotted lines in FIG. 1, the conventional OTR microwave oven sucks combustion gas and polluted air generated in cooking using the gas range which is installed at the lower side through the air suction port 6 which is formed on the lower surface of the outer casing 3. The sucked air is ventilated by being discharged to the outside through the air discharge port 7 which is formed on the upper surface of the outer casing 3 through the flow path 2 or is circulated indoors.
Meanwhile, as shown in FIGS. 2 and 3 the blower apparatus 4 of the conventional OTR microwave oven includes a bracket 42 which is combined with both sides of the motor 41 positioned in the center portion, a centrifugal fan 43 which is combined with a rotation shaft (not shown) of the motor 41 which is protruded to the outer side of the center portion of the bracket 42, and a cylindrical fan housing 44 having a side which is fixed with the bracket 42, which is combined to cover an outer side of the centrifugal fan 43.
In the fan housing 44, a suction port 45 for sucking air is formed at the outside, and a discharge port 46 for discharging the sucked air of the suction port 45 is formed in the vertical direction to the suction port 45.
Also, a cut-off portion 47 for guiding the discharged air is formed at a side of the discharge port 46.
In the conventional blower apparatus 4 with the above composition, the centrifugal fan 43 which is shaft-coupled with the motor 41 rotates when the motor 41 rotates as a power source is applied, and the outer air is sucked into the inside the fan housing 44 through both suction ports 45 of the fan housing 44 as a suction force is generated by rotation of the centrifugal fan 43.
In addition, the air sucked into the fan housing 44 through the suction port 45 is discharged to the discharge port 46 which is formed in the vertical direction of the suction port 45 by the rotation force of the centrifugal fan 43.
However, in the conventional ventilating fan 4, air flow which is formed by rotation of the centrifugal fan 43 forms a wide loss regions by growth of the boundary layer in the edge portion of the discharge port 46, and such flow loss in the discharge port 46 hinders the blowing amount, and increases blade passing frequency (hereinafter, as BPF) noise of the centrifugal fan 43.
As a method for solving the above problem, the present applicant has suggested a method for forming the cut-off portion as a xe2x80x9cVxe2x80x9d shape in the discharge port 46 disclosed in U.S. Pat. No. 6,200,093.
However, in case of manufacturing the fan housing in which the xe2x80x98Vxe2x80x99-shaped discharge port suggested by the present applicant by plastic injection molding, an under cut was generated, and accordingly, designing of the plastic injection molding which can be mass-produced was difficult since a loose core or slide core and the like must be installed and used in the metallic patterning of the fan housing.
Therefore, an object of the present invention is to provide a blower apparatus having a structure with which a fan housing having a xe2x80x98Vxe2x80x99-shaped discharge port therein can be easily manufactured by injection molding of plastic without installing a loose core or slide core.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a blower apparatus, including a centrifugal fan, a driving unit for rotating the centrifugal fan, a bracket combined with a side of the driving unit, and a fan housing receiving the centrifugal fan, the fan housing being combined with the bracket, and having a suction port formed in a shaft direction of the centrifugal fan for sucking gas by rotation of the centrifugal fan, and a discharge port formed vertically to the suction port for discharging gas sucked through the suction port, wherein an edge of the discharge port is in a convex shape in the shaft direction formed by a first inclined surface of a protrusion portion which is protruded in the shaft direction from the bracket and a second inclined surface in the fan housing.
The centrifugal fan, bracket and fan housing can be installed as a pair at both sides of the driving unit.
The present invention also provides a method for manufacturing a blower apparatus which includes a centrifugal fan, a bracket combined with a side of the driving unit, and a fan housing being combined with the bracket, receiving the centrifugal fan, the fan housing being combined with the bracket, and having a suction port formed in a shaft direction of the centrifugal fan for sucking gas by rotation of the centrifugal fan, and a discharge port formed vertically to the suction port for discharging gas sucked through the suction port, by forming an edge of the discharge port in a convex shape in the shaft direction with a first inclined surface of a protrusion portion which is protruded in the shaft direction from the bracket and a second inclined surface in the fan housing.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.